The present invention relates to processes for the preparation of polymers, including homopolymers, random copolymers, block copolymers, functionally activated polymers, and the like, and more specifically, to a polymerization process and to the polymers, or resins formed thereby, and especially to processes for the preparation of multiblock, such as copolymers of styrene acrylates. In embodiments, the present invention relates to stable free radical processes for generating a thermoplastic polymer resin or resins, with narrow polydispersities, that is narrow molecular weight distributions as indicated by the ratio M.sub.w /M.sub.n, where M.sub.w is the weight average molecular weight and M.sub.n is the number average molecular weight, and easily controllable modality, from at least one, and for example from 1 to about 10, comprising heating for an effective period of time a mixture of a free radical initiator, a stable free radical agent, and at least one polymerizable monomer compound, for example, wherein at least one is from 1 to about 5, and preferably one, in the presence of a base like an alkali metal base, such as cesium hydroxide, under conditions that all polymer chain formations are initiated at about the same time; cooling the mixture to effectively terminate the polymerization; isolating the thermoplastic resin product; and optionally washing and drying the polymer resin product. The polymer generated by the process of the present invention in embodiments are essentially monomodal and in embodiments by repeating the heating, there is provided a method for obtaining mixtures of monomodal polymer resins that are compositionally the same resin type having characteristics of both narrow polydispersity and known or selectable modality. In embodiments, the process of the present invention provides a method for conducting bulk or neat free radical polymerization processes on multikilogram or larger scales. The aforementioned embodiments may be accomplished in a one or single pot reactor environment. Further, in embodiments polymeric chain growth proceeds by a pseudoliving mechanism and can provide thermoplastic resins of variable molecular weights from very low to very high, for example less than about 2,000 up to about 400,000, or greater, preferably about 200,000, while maintaining narrow molecular weight distributions or polydispersities of, for example, about 1.05 to about 1.95 and wherein the monomer to polymer conversion is high, for example at least about 50 percent, and more specifically, from about 50 to about 99 to 100 percent. Moreover, in embodiments block copolymers can be synthesized by the aforementioned stable free radical moderated free radical polymerization processes, wherein each block formed is, for example, well defined in length by the reacted monomer, and wherein each block formed possesses a narrow molecular weight distribution, and wherein the block copolymer is substantially 100 percent block copolymer and not contaminated with the formation of a homopolymer of the second monomer.
With the present invention in embodiments thereof there are provided stable free radical polymerization processes wherein inhibition of the thermal polymerization of monomers like styrene is minimized with a base, and wherein high M.sub.w polymers, such as from about 100,000 to about 250,000, are obtainable, and wherein in embodiments the autopolymerization of monomers, such as styrene, can be minimized or reduced in the presence of bases.
The polymer, resins, and the like obtainable with the processes of the present invention can be selected as toner polymers, as thermoplastic films, and as coatings.